Guantánamo Bay Briton to sue UK government

Shaker Aamer whose release has been repeatedly requested by British ministers, blames the security and intelligence agencies for his continuing detention. Photograph: Getty

The last remaining British resident held in Guantánamo Bay has accused MI5 and MI6 of making false and highly damaging claims about his alleged involvement with al-Qaida and is suing them for defamation.

Shaker Aamer, whose family and children are British, and whose release has been repeatedly requested by British ministers, blames the security and intelligence agencies for his continuing detention.

His lawyers have now written to William Hague, the foreign secretary, and Theresa May, the home secretary, demanding an explanation for the false claims they say UK officials have made against him to the CIA, and an admission that his indefinite detention constitutes a war crime. They point out that Aamer has repeatedly implicated British officials in his mistreatment in Afghanistan and Guantánamo Bay – allegations which are now being investigated by the Metropolitan police.

"One of the most serious, knowingly false statements made by the UK security services is Mr Aamer is an al Qaida member who was part of al Qaida in London," say his lawyers.

Claims he was associated with mosques which served as an "attack planning and propaganda production base for al Qaida" are "emphatically false", they have told Hague and May. They add: "Mr Aamer emphatically denies that he is a member of al Qaida. He never has been." Aamer has not been charged with any offence. He was rendered to Guantánamo in 2002.